The inversion of melatonin circadian rhythm secretion in some alcoholics during both intake and acute withdrawal has been widely reported. In the same way, what happens to this inversion when these patients are in long-term withdrawal is not known. To document this abnormality in alcoholics after withdrawal we investigated melatonin secretion observed during chronic alcoholization and after withdrawal.

Our results show that this reversed rhythm of melatonin secretion as seen by the diurnal excretion of 6SM (6SM/creatinine ratio) persists during acute withdrawal in more than half of the patients and is still present 15 days after withdrawal in three patients.

It is remarkable that the inversion of the melatonin rhythms gets corrected in four out of seven patients after withdrawal. But, the circadian disorganization of melatonin secretion in three patients could underline a desynchronization in some alcoholic patients and may indicate more widespread circadian temporal structure disturbances in these patients.